Many printing devices use a rotating imaging member that receives marking material and transfers the marking material to print media. For example, solid ink printers include a rotating imaging drum. The solid ink in the printer is melted and deposited on to the drum. The drum then transfers the ink to paper.
The imaging drum in such printing devices is rotated and the paper comes into contact with the drum as it rotates. An electric motor is used to rotate the drum via a drive mechanism. The drive mechanism may include a gear drive as well as a drive belt which is operably connected between a motor pulley and a drum pulley. The drive belt is typically provided in the form of a v-belt which links the motor pulley to the drum pulley. The motor pulley is grooved to match the belt profile and the drum pulley may be grooved or flat. The v-belt relies on friction to transmit torque between the drive motor and the drum. The torque capacity of the printer is dependent in part on the belt tension and the coefficient of friction between the belt and pulleys.
In certain situations, the friction between the belt and the pulleys is insufficient to drive the imaging drum and the belt slips on one of the pulleys. Excessive belt slip between the motor and the drum may result in belt damage and objectionable noise.
A number of factors can cause variation in the torque capacity of the belt drive system. These factors include, but are not limited to (i) residual mold release agent being left on new belts; (ii) drum release agent (e.g., silicone oil) contaminating the belt or pulleys; (iii) improper belt tension as a result of various factors (e.g., improper spring installation or improper binding of the motor pivot interface); and (iv) belt wear.
Even if the belt is clean from contaminates, relatively new, and properly tensioned, a “normal” belt drive may slip when an unexpected high torque event occurs. Such unexpected high torque events include, but are not limited to (i) pressure roller attempts to climb a leading media edge under an excessive transfix load; (ii) multipick or shingled media delivered to the transfix nip causing the pressure roller to climb the leading edge of the shingled media; (iii) commanding excessive drum accelerations; (iv) a loss of servo control of the drum drive yielding unexpected high accelerations; or (v) an excessive transfix load.
In view of the foregoing, it would be desirable to provide a printing system capable of preventing belt damage or excessive noise due to belt slip. It would also be desirable to provide such a system that may also be used to identify a faulty drive system, worn belt, or events that cause excessive belt slip.